Research
Below are some of my current projects, collaborations and a list of opportunities to join the group.
There is also a dedicated page for past projects and results.
Current projects
My research investigates turbulent processes in the coastal ocean, in other words, how ocean flows and turbulence transport heat, salt, nutrients and pollutants, shaping coastal environments. Combining field observations, laboratory experiments and computer simulations, I aim to build the physical understanding needed to better predict and protect these environments as climate change and human pressures intensify.
Hydrodynamics and transport processes in coral reef restoration
Coral reefs support remarkable biodiversity, coastal protection and livelihoods, but are increasingly threatened. Restoration can help damaged reefs recover, yet its success depends on local environmental conditions. Working with researchers and restoration organisations in Bali, Indonesia, I am investigating how currents, waves and temperature variability shape the conditions corals experience. I am also interested in how restoration structures alter water movement, influencing heat exposure, nutrient supply and larval transport and settlement. Combining field observations, laboratory experiments and computer modelling, this research aims to inform where and how reefs are restored, helping practitioners select suitable sites and design restoration layouts that best support coral survival, growth and ecosystem recovery. The goal is to connect reef hydrodynamics with ecological recovery to guide more effective restoration to stop the rapid decline of coral reefs.
Revealing shear instabilities in estuaries with multibeam sonar imagery
In most of the ocean, including estuaries, denser water layers lie below lighter ones. In such stably-stratified systems, turbulence is often initiated by shear instabilities triggered by tidal forces or underwater topography. Instability grows into a beautiful coherent wave structure, as visualised above by sonar from an autonomous underwater vehicle in the Connecticut River estuary. This growing underwater wave then breaks into disorganised turbulence, mixing the layers. We are currently analysing game-changing multi-beam sonar imagery of turbulent mixing collected by US collaborators. These observations reveal that mixing does not always occur by breaking in the ‘cores’ of the wave on a scale of 1 m (seen above), but also by smaller secondary shear instabilities along the ‘braids’ on a cm scale (see yellow regions above) These findings provide new insights into the turbulent 'energy cascade' from large to small scales controlling the mixing rates of salt, nutrients, dissolved gasses, etc.
Collaborations: W. R. Geyer (Woods Hole Oceanographic Institution), C. Bassett (U. Washington)
Measuring stratified turbulence in the lab with high-speed laser and cameras
To complement direct observations, laboratory experiments are crucial, like the Stratified Inclined Duct (SID, pictured above). This experiment, which I developed at Cambridge, uniquely sustains geophysically-relevant stratified turbulence under more controlled conditions than in the field. It also allows us to measure the flow with much higher resolution and accuracy using fast lasers and cameras to perform simultaneous, 3D Particle Image Velocimetry and Laser Induced Fluorescence. These data led to breakthroughs on the energetics of sustained stratified mixing and 3D coherent structures (see past projects). We are now extrapolating these findings from the laboratory scale to the geophysical scale using theory and models developed in tandem with observations (see above) and simulations (see below). Imaging stronger and faster turbulence with higher-speed laser and cameras (up to 1 kHz) would be an exciting research frontier to pursue for an ambitious PhD or postdoc.
Collaborations: X. Jiang (Peking U.), S. B. Dalziel, P. F. Linden (DAMTP, U. Cambridge),
Probing the finest scales of mixing with exascale simulations on GPU clusters
Computational fluid dynamics is a precious tool to complement field observations and laboratory experiments and build better models of turbulence. To do this, we must solve the 200-year-old Navier-Stokes equations governing turbulence on massive grids because of the extreme range of scales involved. This is particularly challenging in stratified turbulence, because the energy cascades down to microscopic scales. The ground-breaking simulations that we are currently analysing (pictured above) faithfully reproduce for the first time, the same kind of mean-shear-forced turbulence observed in the field and lab experiment. These simulations were pioneered by collaborators in the USA on the world's first exascale computer, Frontier. They involved tens of thousands of GPUs, performing in parallel several billion billion operations per second (exaFLOPS), and are also challenging to analyse!
Collaborations: M. Couchman (York U., Toronto), S. de Bruyn Kops (U. Massachusetts Amherst) and others in the STRATA group: Supercomputing for Stratified Turbulence Research Advancing Theory and Applications.
Group
We are looking for students and postdocs to join the group. Get in touch if the above research sounds exciting and you have a strong quantitative background (physics, mathematics, engineering or similar degree).
Current members
2026 -
Asad Naqvi (PhD candidate)
“Laboratory investigation of ocean mixing by stratified turbulence”
PhD opportunities
I currently advertise two projects for 2027. Other projects can be designed together with motivated students.
PhD Opportunity: Hydrodynamics of coral reef restoration [click for pdf]
PhD Opportunity: Unravelling turbulent mixing through exascale simulations [click for pdf]
Sources of funding:
There are no fully-funded projects available at the moment.
We may be able to support students applying for the following schemes:
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Competitive scholarships are available from Imperial College and Civil and Environmental Engineering, with various eligibility criteria.
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Mathematics for our Future Climate: Theory, Data and Simulation (MFC) Centre for Doctoral Training (CDT) for a start in 2027.
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External scholarships from foreign governments or private foundations also exist, such as the Chinese Government Scholarships or the Croucher Scholarship (Hong Kong).
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For more information, see Imperial's comprehensive 'Scholarships' page, and its search engine.
Postdoctoral opportunities
There are no funded postdoctoral jobs available at the moment.
Researchers interested to join my group can apply for their own project and funding through fellowships, such as:
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Royal Society International Newton Fellowship (including the K C Wong Fellowships for Chinese applicants)
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Royal Commission for the Exhibition of 1851 Research Fellowship
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Swiss National Science Foundation 'Postdoc.Mobility' for applicants from Switzerland
... and probably many others. Each scheme has a particular set of strict eligibility criteria.
Fellowships are very competitive and require applicants to propose and lead their own independent project.
For this reason, please only get in touch if you already have your own research ideas and a plan to develop them.
Past members
2025
Emma Bouckley from University of Cambridge (PhD Applied Mathematics, WHOI GFD Project)
“Secondary braid instabilities in Kelvin-Helmholtz at high Reynolds numbers” (theory & numerics)
Jake Hewison from University of Cambridge (MMath Mathematics)
“Do fish mix the ocean?” (experiments)
2024
Valentin Samson from École Polytechnique (MSc Engineering)
“Direct numerical simulations of stratified turbulence” (numerics)
Daniel Ward from University of Cambridge (MMath Mathematics)
“The transition(s) to turbulence viewed through the lens of laboratory experiments” (essay)
2023
Marvil Cheung from University of Cambridge (MMath Mathematics)
“Reduced-order modelling of intermittency in stratified turbulence” (numerics)
2022
Arianna Cox from University of Cambridge (BA Mathematics)
“Machine learning to the rescue of big data: classifying experimental stratified turbulence” (numerics)
Stasiu Wolanski from University of Cambridge (BA Physics)
“High-speed, high-resolution imaging of early bubble growth in decompressed hydrogels” (experiments)
Jason Tang from University of Cambridge (BA Mathematics)
“Modelling of the transition from elastic cavity to fracturing crack in decompressed hydrogels” (theory)
Keshav Raghavan from University of Cambridge (MMath Mathematics)
“Data assimilation and super-resolution reconstruction of experimental turbulent flows” (essay)
2021
Aly Kombargi from Ecole Polytechnique (MSc Engineering)
“Early-stage growth of gas-filled cavities in decompressed hydrogels” (experiments)
2020
Yansheng Zhang from University of Cambridge (BA Physics)
“Giving hydrogels the bends: experiments” (experiments and theory)
Zhiyuan Wei from University of Cambridge (BA Physics)
“Elastic modelling of spherical and fracturing bubbles in soft brittle solids” (theory)
Joshua Cudby from the University of Cambridge (BA Mathematics)
“Weakly nonlinear Holmboe waves” (theory & numerics)
2018
Yves-Marie Ducimetière from EPFL (MSc Engineering)
“The effects of confinement in stratified shear flows” (theory & numerics)
2017
Ling Qu from South China Sea Institute of Oceanology in Guangzhou, China (PhD visitor)
“Experiments on buoyancy transport in a stratified inclined duct” (experiments)